Ted Cruz and John Kasich are joining forces in a last-ditch effort to deny Donald Trump the Republican presidential nomination.

Within minutes of each other, the pair issued statements late Sunday saying they will divide their efforts in upcoming contests with Cruz focusing on Indiana and Kasich devoting his efforts to Oregon and New Mexico. The strategy — something the two campaigns have been working on for weeks — is aimed at blocking Trump from gaining the 1,237 delegates necessary to claim to GOP nomination this summer.

The extraordinary moves reflect the national strength Trump has shown and the inability of Republicans who oppose the New York billionaire to come together to stop him. Dividing up some of the remaining primary states by putting forward one strong alternative to Trump in each could be enough to take away delegates and curb Trump’s run to the nomination.

Trump is the only candidate who can realistically get a first-ballot victory — there’s no mathematical path for Cruz or Kasich to clinch the nomination heading into the convention. The billionaire is poised for a strong performance Tuesday, when Republicans in Maryland, Pennsylvania, Delaware, Connecticut and Rhode Island head to the polls.